Laminated sheet material for use in making paper bags or wrappers



7!!!!I/lflllfllllrllllll 3 Sheets-Sheet 1 FIIIIIIl/flllfllrltrlflllr/lrlIll/Ilf/ll/llllfllfl! T. A. HODGDON ET AL LAMINATED SHEET MATERIALFOR USE IN MAKING PAPER BAGS OR WRAPPERS Filed Sept. 16, 1936 I May 16,1939.

I N V E! YTOR 5, new ,1 110472011, BY f lfladydolz,

ATTORNEY.

May 16; 1939.

T. A. HODGDON El AL LAMINATED SHEET MATERIAL FOR USE IN MAKING PAPERBAGS OR WRAPPERS Fil'ed Sept 16, 1956 5 Sheets-Sheet 2 INVENTORi ZeadamJZ 170470 0 flzalfiffimfqdazz,

ATTORNEY May 16,1939. T. A. HODGDON ET AL LAMINATED SHEET MATERIAL FORUSE IN MAKING PAPER BAGS 0R WRAPPERS 3 Sheets-Sheet 3 INVENTORSATTORNEY.

Patented May 16, 1939 LAMINATED SHEET MATERIAL FOR USE IN MAKING PAPER.BAGS OR WRAPPER/S Theodore A. Hodgdon, Wilbraham, Mass., and

, Paul E. Hodgdon, Readsboro, Vt.

Application September 16, 1936, Serial No. 101,098

3 Claims.

This invention broadly comprises means for laminating a plurality ofwebs of sheet material of what is known as hydrated sulphite pulp, or inthe trade, as glassine paper which possesses a high degree of hydrationand having highly calendered surfaces, so that it is practicallygrease-proof. It may also be made moistureproof when coated, or treated,with moisture-' proof materials,

One of the objects of the invention is to coat the base, or transparentglassine sheet of the bag-forming material with a suitable wax, thatserves the double purpose of rendering the paper transparent, and, as anadhesive for binding the 1 layers or webs of the paper together.

' At the present time, bag manufacturers wishing to produce a bag with atransparent window in its fr nt, back, or sides, must usually perform acombining operation of the transparent strips with the opaque strips,before the completed bagforming material may be put through a bagformingmachine; The present invention is designed to remove this objection andto produce a laminated sheet having the requisite number 5 of layers andhaving a transparent window, or a series of windows, wherever desired inthe finished bag, and, ready for a bag-forming machine; thus lesseningthe cost of manufacture of the bags.

. A further object is to provide a sheet of laminated bag-forming andwrapping material that is formed with perforations, or openings, in aside or sides, of the outer covering of the lamination on its outersurface, of the finished bag, so that the contents may be readilyobserved through the transparent base sheet of the bag.

A further object is to provide a bag-forming, or wrapper sheet, in whichits entire inner surface, or base piece, is composed of transparentglassine material, and substantially grease-proof, and nonabsorbent ofwax, whereby the contents of the bag may be protected throughout itsentire inner surface.

This invention is particularly designed for making laminated sheetmaterial from glassine, which is a paper made from thoroughly hydratedsulphite pulp, and having highly calendered surfaces, so that it issubstantially grease-proof and non-absorbent of wax. It is designed toproduce a bag having a transparent base member that is laminated withstrips, or, with a full-width opaque perforated member.

An object of the present invention is to supply,

for. wrapping and bag-making purposes, a

laminated sheet material which will be an im- 55 provement from astandpoint of flexibility. that is;

more able to withstand bendin folding and creasing, as on a bag orwrapping machine, without easily separating, opening or coming apart atthe creases, or folds. This is accomplished by applying a coating ofwax, which, when cooled, will remain in a thin, plastic film on both ofthe opposing surfaces which are to be pressed face to face, thus addingto the flexibility of each sheet, even before lamination, thus adding tothe total or final flexibility of the laminated sheet.

Means is provided for cooling the laminated sheet, as it leaves thepressure rolls and a second roll is provided, spaced some distance fromthe cooling roll of smaller diameter. The laminated web, from thissecond roll, now passes around two cooling rolls I1 and I8, preferablyof a temperature of about F. A take-up, or winding roll, for thecompleted sheet, is employed, and a suitable tension roller interposedbetween the takeup roll and the cooling rolls.

Further objects and nature of the invention will appear in the body ofthe specification with reference to the drawings and the appendedclaims.

Referring to the drawings:

Fig. 1 shows means for applying the transparent coating material to thebase or transparent sheet on one surface only, and on the under surfaceof the three opaque strips which receive their coatings of wax from thesame coating supply which is in the receptacle through which the basesheet passes, or is drawn, and which material is'carried up to the nip,by the rotating of the lower pressure roller.

Fig. 2 is a section of the finished laminated sheet, before the same isslitted to form the individual wrapping, or bag-forming material, shownin Figs. 3 and 4.

Fig. 5 is a detail view of a detached portion of the laminatedbag-forming material, or wrapping material, before it is folded to forma bag or wrapper.

Fig. 6 is a detail view, showing diagrammatically a machine for coatingboth surfaces of the opaque and transparent base sheets of glassinematerial. Fig. 7 is a perspective view, showing one of the folded bagswith the full length transparent window of the base material extendingthe full length of the frontof a finished bag.

Fig. 8 is a cross sectional view on the line 8-8 of Fig. '7, showing thelining of the transparent base material extending over the entire innersurface of a bag. t

Fig. 9 is a longitudinal sectional view on theline 9--9 of Fig. 8,illustrating the folded ends of a bag and the inner member oftransparent material.

Fig. 10 is a modification of a completed bag, illustrating a window orperforation in the opaque material disclosing the inner transparent basemember.

Fig. 11 is a view similar to Fig. 10, showing different shapedperforations in the opaque material of the bag as trade-marks as well aswindow openings in the opaque material.

Fig. 12 is a modification in which the outer or opaque layer is coatedon one side only with a wax of low melting point for flexibility andadhesive qualities, while the other sheet or base transparent sheet iscoated all over on its surface with high melting point wax, and for onlya portion of its other surface with high melting point wax, so thatthose portions of the transparent base sheet which are covered by theopaque strips, will be left free of the high melting point wax, and thecentral portion of the transparent base sheet, which in the finishedsheet forms the transparent window, will be coated on both sides forgreater transparency and higher polish as produced by the high meltingpoint wax.

Fig. 13 is a view on the line |3-l3 of Fig. 12, showing the mask meansfor preventing the wax from being applied to the opposite edges of thetransparent base web of paper, and on which edges the opaque webs aresecured having the low temperature melting point wax, or other adhesivethereon.

Fig. 14 is a cross sectional view on the line l4-l4 of Fig. 12, of thefinished web, shown in Fig. 12, illustrating the high temperaturemelting point wax for imparting a polish and the low temperature meltingpoint wax for adhesive qualities and for flexibility.

Fig. 15 is a further modification, showing the rotary perforating diemeans for forming openings in the single, outer opaque web covering offull width, by means of a pair of rotating dies.

Fig. 16 is a view of another form of finished bag material havingwindows, and showing in dotted lines where the laminated bag material isseparated by the bag-folding machine, to form the individual bag, orwrapping sections.

Referring to the drawings in detail:

I indicates a supply roll of the transparent glassine material whichpasses over the tension, or adjusting guide roll 2. The roll I issupplied with a suitable brake device, (not shown), for adjusting therate of travel of the unwinding of the web. 3 is a supply tankcontaining the suitable coating waxes, in which the pressure roll 4 ispartially submerged. The web, from the roll I, is drawn tightly aroundthe bottom surface of the roll 4, to prevent the admission of the wax,between the web and the roll, and thus keep the inner surface of the webdry. The wax, in the receptacle 3, may be heated, according to therequirements of the material to be laminated. It, therefore, receives acoating on its under surface, or, as indicated at 5. 6, 6 and 6"designate three independent rolls of opaque glassine paper from whichthe three opaque strips I, 8, and 3 are drawn over the tension roll III. The rolls 5, 5 and 5" each have an independent brake device. Thesestrips engage, or come into direct contact with the wax, 3, on the undersurface 5, of the transparent, full width base sheet 'I of transparentglassine material, throughout their full widths of their under sides,which excludes the air and aids in the adhesion at the nip of the rolls.They pass under the upper pressure I l which, with the roll 4, operatesto cause the webs to adhere and form the laminated web l2, leaving thetransparent portions l3 and M. The material 3 serves the double purposeof protective properties and as an adhesive. The web l2 passes over theadjustable and cooling, or drying roll l5 having a temperature about 70F.; then, over the second adjusting roll I6; then over and under thecooling, or drying coils I1 and I8 having a temperature of 180-190 F.,the tensioning roll I9 and the takeup roll 20. The strips 1, 8, and 9serve to provide the opaque strips, or portions, of the finished bag andwrapping material.

The wax, is, in every case, substantially moisture-proof, as well aspolished in appearance when dry or cool; thus, it serves a triplepurpose; (ll) adheres the opaque strips to the base sheet; (b) impartsprotective qualities to the base sheet; and (0) increases thetransparency and polished appearance of the transparent strips of thebase sheet; that is; the portions of the transparent base sheet whichare not covered by the opaque strips. The temperatures used in the rollsl5, l1 and I8 have been referred to above.

It will be seen, from Fig. 1, that the center opaque strip 8 isapproximately twice the width of the opaque strips 1 and 9, but notexactly, and this strip is later slitted along the medium line 2| toform the two bag-wrapping finished members, shown in Figs. 3 and 4, inwhich the middle web 8 defines the two marginal opaque strips 22 and 23and the visible transparent portions of I3 and I4.

Referring to Fig. 5, the finished laminated web I2 is shown with thesevered edges 24 and 25,

which represent the length of one of the finished bag elements, beforeit is finally folded by the bag-making machine. This view shows thepartial folds, or crimps, of the bag at 26 and 21; the finished bagbeing indicated in Figs. 7, 8, and 9, in which the full widthtransparent, base material l of glassine extends completely around onthe entire inner surface of the bag, which is an important feature ofour invention, to protect the contents and to increase the thickness ofthe bag.

Actually, the transparent base material is, at this point, not onlygrease-proof glassine, but has been rendered moisture-proof, as well, inthe operation shown in Fig. 1. Thus, we might say in which the fullwidth transparent base sheet I of coated glassine extends completelyaround on the entire inner surface of the bag, which is an importantfeature of our invention, inasmuch as the base sheet is of a highlygrease-proof glassine to start with, and is coated with moisture-proofmaterial in addition, to protect the contents.

It will be seen from the description of the apparatus, shown in Fig. 1,that the takeup roll 20 is a finished laminated web, ready for thebag-forming machine, and does not require any further building up of thestrips for forming the bag material, before it is folded on a bag-foruming machine.

Referring to Fig. 6, in which the supply roll 28 of the transparent baseglassine sheet passes over the tension roll 29 and under the lowerpressure roll 30, which is partially immersed in a tank of coating wax3|, the web 32, then passes under the submerged roll 33. This web istherefore coated on both sides, as it leaves the roll 33. A second web34, from a second supply roll 01' opaque glassine material, passes underthe sub merged roll 35, which i:-'. in the same paraffin coating wax,located in the tank 3!, where it is Yll also coated on both ofiitssides, as shown, for laminating and for transparency. The two webs thencome together and are forced into close contact by means of the pressurerolls 30 and 36, to form the finished web 31. This web is thereforecoated on both of its upper andlower surfaces, with the coating wax, aswell as on the two inner surfaces for increasing its transparency. I

Therefore, it is to be understood that the view shown in Fig. 6 coatsboth sides of the base sheet, as well as the two opaque side strips,corresponding to strips 1, 8, and 9 in Fig. 1.

Thus, a bag may be formed having a transparent window the full length ofits face or sides, fully coated with moisture-proofing material all theway around on both its inner and its outer surfaces.

Referring to Fig. 12, which illustrates means for coating thetransparent base sheet over the entire width of one of its sides orsurfaces with a wax, having a high degree melting point, then I coatingonly a strip of its opposite surface with the same high degree meltingpoint wax, leaving side portions of the base sheet uncoated, said sideportions to later receive a coating of low degree melting point wax orother knownadhesive, at the time they are covered by the opaque strips.I

In this apparatus, there are two supply rolls 42 of opaque glassinepaper which pass under the waxing roll 43, which is partially immersedin the supply tank 44 of low degree melting point wax, and coats oneside only of the opaque web strips 42' from the rolls 42, as shown inFig. 12. The webs then pass over a doctor element 45 to remove anysurplus and under the lower pressure roll 46, of the drip tank 41. Atthis point they are drawn upward to the other upper pressure roll 48,where they meet the web 49 of transparent glassine material from thesupply roll 50.. The glassine, fromthis web, engages the waxing rollwhich rotates-in a bath of high melting point coating wax 52,,and iscoated on its entire lower side only; then, around the conditioning roll53 that is steam-heated; then over the waxing roll 54, which is locatedin the supply tank 55, of wax of high melting point, as I in tank 52'.In this construction, it is desirable that only the upper center portion56 (see Fig. 13), be left with the transparent coating wax 52 of highmelting point to give it a polished surface. 51 and 58 are mask elementslocated on the rod 59 and adjustable to prevent the under surface of theweb 49 from taking up any of the high melting point coating wax 52 atthe opposite under side edges of the web 49, from the roll 54, wherebyportions of the opposite side edges of the web 49 are left dry forreceiving the webs of-opaque materiaLfrom the two rolls 42 and is forcedinto contacttherewith by the rollers and 48. This operation produces thelaminated bag material for forming the bag shown in Fig. 7; that is tosay; with the central portion that is transparent and extends the fulllength of the bag. The finished laminated web 60 is then passed aroundthe cooling and tension rolls 6| and 82 and over and under the coolingand drying rolls 63 and 54, which have therein a cooling, or dryingtemperature medium, depending upon the coating material used, asdescribed, to the final takeup 65.

Referring to Fig. 15, which is the same as Fig. 12, with the exceptionsthat the opaque web is full width from the supply roll 42" that passesor article, shown in Fig. 10.

It is particularly understood that the finished bag material that isformed, as described, is of a grease and moisture-proof nature, as wellas transparent. The transparent portions are for inspection of thecontents. The opaque portions give a clean, white appearance to thepackage 7 as well as a double thickness.

Thelaminated sheet material, having a transparent base material andopaque strips, is a complete and finished article, ready for the bagmanufacturer, and, whether with the continuous window, or the openingsof various forms in the opaque material, as shown in Fig. 11, are used.This article is, therefore, of double thickness.

It should be particularly understood that we do not limit ourselves tothe size, number, or location of the transparent window portions of thebag or wrapper, as they can be extended to cover the entire surface orface of the package, as well as portions of the sides and ends, thusmaking the transparent window portion of the package much larger thanthe laminated portion. The 'folds or'bends therefore, are not limited tothe area which is laminated, or of double thickness.

It should be further understood that while an important feature of ourinvention is the transparent base sheet of full width, that is;extending all the way around the inside of the bag or wrapper, thusgiving maximum protection to the contents of the package, it is possiblewhen desired, to supply the base sheet not in full width, in order tomake a portion of the side edges of the laminated sheet of singlethickness, rather than double thickness, with the object of using lesspaper and for making a seam or joint at the back or bottom of thepackage which will be less bulky than when the base. sheet does extendall the way "to the edges of the opaque member.

We do not, therefore limit ourselves to a base 1. A laminated sheetcomprising, a base member-of transparent glassine, a transparent waxcoating covering one surface, its opposite surface having a transparentwax coating thereon, opaque glassin'e strips secured to the secondcoating at the opposite" side edges but spaced apart atthe centerportion of the base member, whereby the two coatings of transparent waxrender the center portion more transparent.

2; As an article of manufacture, a sheet of greaseproof andmoistureproof glassine paper, both surfaces of said sheet having acoating of wax for imparting to said sheet a glossy finish, one surfaceof said sheet having strips of opaque glassine paper superposed thereonand spaced from the center lineof said sheet.

3. A .laminatedsheet for wrapping paper and bags, comprising a basesheet of ;transparent glassine paper, said base sheet being providedwith a continuous thin film of transparent wax on both surfaces, aplurality of strips of opaque glassine secured on the upper surface ofsaid base sheet and parallel to the side edges of said base sheet andspaced from each other, the film of wax on the upper surface of saidbase sheet serving as a. binder for securing said opaque strips on saidbase sheet, the coating of transparent wax on both surfaces of said basesheet serving to increase the transparency of the exposed portions ofsaid base sheet.

THEODORE A. HODGDON. PAUL E. HODGDON.

